Friction stir welding (FSW) is a solid-state welding process that uses a non-consumable rotating tool to connect two workpieces. This process softens the material through friction heating and mechanical stirring, thereby achieving material bonding. FSW is particularly suitable for welding refractory metals such as aluminum alloys because it can avoid problems such as pores and cracks that are common in traditional fusion welding.

Marine aluminum alloy materials manufactured using friction stir welding (FSW) technology mainly include 5xxx series (such as 5083, 5086) and 6xxx series (such as 6082, 6061), among which ribbed plates are widely used in key structural parts such as ship decks, side plates, waterproof wall plates, bottom outer plates and superstructures.

Specific application of ribbed FSW panels in ship structures:

- Hull deck and side plates

Friction stir welded ribbed plates form a lightweight and high-strength deck structure by splicing wide aluminum alloy profiles, significantly reducing the weight of the hull and increasing the load-bearing capacity. For example, the "catamaran wave-piercing boat" developed in my country uses this technology.

- Waterproof wall panels and bottom outer panels

When wide ribbed plates are used for bottom outer panels, their corrosion resistance and fatigue resistance are better than those of traditional welding processes, and they are particularly suitable for areas that are in long-term contact with seawater.

- Superstructure modules

The use of stir-friction welded ribbed plates in ship superstructures (such as cockpits and living cabins) can achieve deformation-free splicing, reduce assembly errors, and improve overall dimensional accuracy.

- Preformed modular structures

Small extruded profiles are connected into large preformed wall panels through stir-friction welding, which reduces the welding workload on site at the shipyard and shortens the construction cycle. For example, the aluminum alloy deck of military missile speedboats uses such prefabricated modules.

In terms of marine aluminum materials, friction stir welding technology has the following advantages:

- High-quality welding: Since the welding process is carried out in the solid state, common defects in fusion welding, such as pores and thermal cracks, can be reduced or eliminated.

- Improved mechanical properties: Compared with traditional welding methods, FSW can obtain more uniform and finer microstructures, which helps to improve the strength and toughness of welded joints.

- Small deformation: Because friction stir welding belongs to low-temperature welding process, the heat-affected zone generated during welding is small, which reduces the deformation caused by welding.

- Environmental protection and energy saving: No additional filling materials and protective gas are required, which reduces resource consumption and environmental impact.

For shipbuilding, using friction stir welding aluminium for marine use can not only reduce the weight of the hull and improve fuel efficiency, but also enhance the corrosion resistance and maintainability of the ship structure. Therefore, this welding technology has been more and more widely used in modern shipbuilding.